Dysfunctional vascular endothelial cells (ECs) contribute to the pathophysiology of several cardiovascular diseases, such as atherosclerosis and its life-threatening complications.1 Gene therapy can be a valuable approach to modulate endothelial cell function for the prevention of atherosclerosis. However, there is still a lack of method for transgene expression in vascular endothelium. Professor Dai Zhifei from College of Future Technology Peking University used ultrasound and microbubble ultrasound contrast agent for clinical diagnosis in combination with adeno-associated virus (AAV) vector to establish a new ultrasound image guided transgene delivery strategy for vascular endothelial cells in vivo (UMGAAV), which realized the spatial regulation of transgene expression in vascular endothelial cells in a non-invasive manner for the first time, and achieved the treatment of carotid plaque in a mouse model. The research findings were recently published online in the Journal of Signal Transmission and Targeted Therapy (IF="38.1) under the title of" Spatial control of robust transgene expression in mouse art under ultrasound guidance ".

To establish the UMGAAV, the research team used a clinical diagnostic ultrasound imaging system with a working frequency of 4.4 MHz, which is also used for clinical carotid artery ultrasound imaging. In color Doppler mode, the carotid artery of the mouse can be clearly seen, and the area of interest can be selected on the image, so that the ultrasound can focus on that area. After the injection of microbubbles, the microbubbles can be selectively blasted in the regioselectivity of interest under the ultrasonic effect from the imaging probe, so as to improve the permeability of the tissues in this area. Afterwards, injecting AAV vector can achieve high specific expression of foreign genes in this region. The experimental results show that ultrasound can increase gene expression in endothelial cells by about 24 times and maintain high expression for more than 8 weeks. In addition, ultrasound also increased the expression of foreign genes in tunica intima and adventitia by about 86 times, indicating that UMGAAV can also be used for gene delivery targeting other vascular cells (such as smooth muscle cells).

In theory, UMGAAV can be used to deliver exogenous genes to all blood vessels visible through ultrasound imaging, except for the carotid artery. The team successfully validated the feasibility of the UMGAAV strategy in the abdominal aorta and femoral arteries of mice. Finally, we further tested the application of UMGAAV in the treatment of atherosclerosis. In the mouse carotid artery partial ligation atherosclerosis model, the targeted delivery of KLK10 gene (a newly identified atherosclerosis inhibitor gene by the team, eLife 2022, 11, e72579) mediated by UMGAAV can significantly inhibit the formation of carotid artery plaque in mice.

In a word, Professor Dai Zhifei' s team has established a new method to achieve selective expression of foreign genes in arterial endothelium through ultrasound image guidance. The ultrasound imaging instrument used in this method has been widely used in clinical practice, and the AAV gene vector has been validated in multiple clinical trials. The microbubble ultrasound contrast agent is independently developed by Professor Dai Zhifei' s team and has been approved by the China Food and Drug Administration. A multicenter phase III clinical trial is currently underway. Therefore, UMGAAV has great clinical conversion potential.

Liu Renfa, postdoctoral fellow, and Qu Shuai, PhD student, 2018, are the co-first authors of the paper. Dai Zhifei is the corresponding author. HanjoongJo from Georgia Institute of Technology and Emory University also contributed to the study. This research was mainly supported by the National Natural Science Foundation of China (No.81930047; No. 82102062) and China Postdoctoral Science Foundation (2020TQ0008).

Paper link: https://www.nature.com/articles/s41392-022-01031-w

INature tweet: STTT (IF="38) | Peking University's Dai Zhifei team achieved transgenic expression in arterial endothelium in vivo for the first time through non-invasive means